Loved every one of these games. In fact, I'm pretty sure I played a couple of them once upon a time, before the series had been finished, and almost completely forgot about them!

My guess is that what Karl says in his study room when you first ''find'' him -''Do you believe this machine can create a fully functioning human?''- is a direct reference to his butler being, in fact, non-human. Especially judging by the fact that when Kara beats him to a pulp, his ''blood'' is black.
I suppose it's all open to interpretation though.

What fantastic ending to a terrific series! So, that explains the experiments in the lab we saw back in episode #2. I won't spoil it, but suffice it to say, the footage from the laboratory is the key to the whole mystery of Karl von Toten's invention.

The only criticism I have is that I'll miss Kara, although her signoff at the end was cathartic. Otherwise, this is an excellent point n'click adventure, and the period setting really helped to set the mise-en-scene, especially with all the crazy looking gadgets. A great sendoff for a truly legendary series.